. . . . and done completely in 'B' Mode you will note - For those here who say this isn't the most efficient way to drive . . . . well, he should be able to do well over a hundred miles if he was using whatever mode you *think* is most efficient, huh?

Don wrote:. . . . and done completely in 'B' Mode you will note - For those here who say this isn't the most efficient way to drive . . . . well, he should be able to do well over a hundred miles if he was using whatever mode you *think* is most efficient, huh?

Don

I think others should do a similar video running in the other gears. I don't know what is more efficient but I like D a lot. Pedal feels great and I like the amount of resistance and if necessary just touch the brake a little but mostly look way ahead and don't need to. I drive on the highway a lot so its probably not that much of a difference for me. I tried B for a long time and didn't notice much of a difference and was annoyed by the pedal feel and response. I kind of feel like if I am very careful I can achieve close to the same thing, at least enough for me to be happy with the balance of the experience and energy savings. I won't be able to contribute a video because I don't have anywhere to go that distance. My challenge is trying to get home from work and back on cold days without charging because I get free charging at work, so there's always the varying temperature involved and my hand on the heater control. So I'll have to rely on the results of someone else's tests to convince me to put it in B on those cold days! I did make a mental note of the B mode while watching the video and I do think it is better in the city but not sure about highway. Seems like when I watch the power indicator and am doing 55-60, and switch between B and D, it tends to stay in lower in eco when I'm in D, on average...if I am very careful with my foot.

I think I have too much of a lead foot for D/B mode, in Eco Mode I can keep the needle more to the left much easier. I haven't had a chance to measure this in Cani0n but I seem to drive more efficiently in Eco Mode. I switch to B mode occasionally when I need to decelerate faster.

When I see traffic slowing/stopping well ahead I find I can glide to a near stop in Eco Mode nicely, in B mode I usually miss and have to accelerate a bit as I am 20-30 feet away from the car in front

ChrisEV wrote:I think I have too much of a lead foot for D/B mode, in Eco Mode I can keep the needle more to the left much easier. I haven't had a chance to measure this in Cani0n but I seem to drive more efficiently in Eco Mode. I switch to B mode occasionally when I need to decelerate faster.

When I see traffic slowing/stopping well ahead I find I can glide to a near stop in Eco Mode nicely, in B mode I usually miss and have to accelerate a bit as I am 20-30 feet away from the car in front

My wife hates Eco mode, says it's like driving a golf cart

Yes I think that's why they call it Eco mode. In one of the i-Miev videos I recently watched on Youtube, someone describing the different gears mentions that Eco mode is the most economical. My take on that is because of exactly what you are saying, for most people, B mode may cause them to drive less economical because of the harshness of the braking which then kills your roll too much and then you spend more energy getting your mo back.

Don wrote:. . . . and done completely in 'B' Mode you will note - For those here who say this isn't the most efficient way to drive . . . . well, he should be able to do well over a hundred miles if he was using whatever mode you *think* is most efficient, huh?

Don

Absolutely! I'm confident I could beat his results by not using B mode (using D and N instead). Two weeks ago I went hiking on 10k trail. Had to do some work related stops in town on the way back. Total of 78.6 miles getting back to the house with 18.5% SOC remaining. Ran the AC and shared it with the battery pack about 65% of the trip. This trip has a 5,000 ft elevation change to get up there. 40% freeway miles, speed limit 65mph. I got lucky on this trip and followed a heavy semi up the freeway section averaging about 50 mph. traffic was running 65 to 70 mph down the same stretch on the way back. Canion doesn't lie! Coasting in N at 140 to 170+ mi/kWh is a "tad" more efficient than in any drive mode at 17 to 21 mi/kWh down the same grade at a constant speed.

For the 97 mile trip (the one with the best efficiency) he averaged 5.35 mi/kWh. On my mountain hiking excursions, I regularly have average round trip efficiency in the 6.6 to 6.9 mi/kWh range. Theoretically at 6.75 mi/kWH (assuming our battery capacity is comparable) 6.75 mi/kWH / 5.35 mi/kWH x 97 miles = 122 miles (on a single charge) would be possible using D and N optimally.

When the red needle is on the letter c in the word "Eco" of the power meter, the car is drawing 25 Amps. When the needle is straight up it is 50 Amps, the next tick to the right is 100 and the last to the far right is 150 A.

Assuming these are full 50 A-hr cells would imply that you could drive for 2 hours at the 25 Amp rate. So at what speed can you maintain while holding the throttle to keep the needle at "c" or less?

An 88 mile trip over 2 hours would be average speed of 44 mph.

Acceleration and hills really cause the red power needle to swing up, usually above the c .

i haven't tested to see how long it takes to accelerate to whatever top speed can be hit while holding 25 Amps. If it is close to 44 mph then theoretically you could make it. But we know that these packs don't allow use of the fully rated 50 A-hr, so that has to be factored into the mix also.

The instant display of power draw on an analog meter is one of the best features of these cars that i really love and enjoy--never get tired of burying that thang and pegging the needle and getting the EV grin.

Bradley's questions are hard to answer- but we can be confident that the driving mode makes absolutely no difference in energy use during steady-state cruising, it only differs during acceleration and deceleration.

I've found N to be useful in the mountains, as at 60+ mph, the i-MiEV's fairly poor aerodynamics create enough drag to not allow acceleration during coasting on even the steepest interstate highway downgrades. Coasting down the hill will get you farther than regenning down and then having to add back power sooner. Regenning down a mountain at say, 35 mph allows significant energy recovery, but going that slowly is not advisable on Snoqualmie Pass during good weather- I don't wanna be the i smooshed on a log truck bumper!

bradleydavidgood777 wrote:Cool! I've often thought that N was a good option for downhill. Doesn't make sense to me to brake even if recharging.

It depends on the circumstances. If you need to go slower than the grade allows for than coasting in N then you should definitely be in a drive mode. I use D for two reasons. I get to use brake lights easily and often, to help keep the drivers behind me out of trouble. It’s right next to N making changing back and forth super easy.

Can you tell us more about your style?

When it comes to “style” the most important thing is to be steady on the accelerator. Also, the further the throttle (or regen brake) input is from the current motor speed the less power efficient the transition is. For example: lets say you are on the Freeway and want to pass from behind a car going 50 mph and a speed limit of 65 mph. If you do so by going deep into the throttle until 65mph is reached. You waste power to motor heating and less efficient battery discharge. If you use a graduated throttle increase (as short as three seconds to increase throttle evenly) it will waste far less power. Most of the “style” habits as I think of them require awareness of upcoming changes and hazards. And an ongoing plan for lane changes etc. Proactive of, not reactive to traffic, etc. Basically, good defensive driving practices.

You say accelerate briskly, so where is your needle during that?

I have found that there is not enough difference between a 2C acceleration and a 3C acceleration to ever use 3C acceleration (except in an “emergency” type situation). 3C acceleration especially at low speeds wastes a lot of power to battery and inverter/motor system inefficiency. That’s the great thing about the iMiev one can move with traffic, or more briskly than traffic off the line easily without going above 2C. So accelerating briskly the needle is between the first mark and the second. When exiting the freeway or approaching a red light I brake very lightly and long so it’s all Regen. After a bit of practice I found it easy to tell where friction braking begins in the brake pedal throw. Avoid it, as best possible. N can be used around town in fewer circumstances but after a while you see opportunities that arise. The car coasts so well in N that on flat ground at low speed (35 mph or so), slowing is gradual enough to not irritate traffic behind me

In what circumstances do you switch to N? Like how long would the hill need to be to be worth the switch?

Anytime that I can coast without exceeding the speed limit by more than 5 mph or without slowing quickly enough to be awkward for those following behind me. If I wouldn’t be in N for more than say 4 seconds, I won’t bother. When I first got canion I did an experiment on a flat road with two stop signs in 4 miles. Did three repetitions in each direction sticking to the 25 mph speed limit on the D call the way runs. on the N comparison runs I accelerated gently to 27 then coasted in N down to 23 mph repeated over and over for the route. Using neutral in this low speed controlled experiment was 6% more efficient averaged over the three (six trips total) runs. I don’t figure it is useful or reasonable in that situation to go to all that trouble for 6%, but interesting that it did work out more efficient to do all the shifting.

When you are on the highway where is your needle and what is your speed?

There isn’t much in the way of flat freeway around here. When climbing to the canyon or climbing through it (speed limit 65mph) the needle will be between the first and second mark on the gauge. Likely averaging halfway between (~1.5C). this can be reduced to more like 1C by drafting near the speed limit. On the way back going down hill maintaining speed in a drive mode it is in the green zone at 17 to 21 amps out of the battery. Shifting to Neutral on long stretches of this freeway decent it goes to zero while speed is maintained or almost maintained. I use drafting quite a bit for the best numbers on the freeway. Always staying 2 seconds back, a Semi truck, RV, Van or large SUV are all good candidates. Drafting on the downhill return leg requires a periodic shift into D to maintain a safe following distance. Since the drafting, reducing aero drag combined with the grade results in a slow build up of speed in N

And anything else you can think of.....

The most important tip is don’t let that Amp needle jump around all over the place it should move slowly and methodically. On a hiking trip drive I average 3.2 to 3.5 mi/kWh (depending on drafting and prevailing winds etc.) when climbing climbing climbing to the trailhead. With lots of coasting and some regen coming back to the valley, that leg of the trip will range between 10.8 and 11.2 mi/kWh. As seen in other parts of the forum. Quantitative analysis shows that only about 25% to 30 % the power used to climb to altitude is returned to the battery by regen. Some of that of course is lost to aero and rolling resistance both directions but still, it is what it is.

IMO B mode is for the most efficient "jack rabbit" driving. "Jack rabbit" driving is by definition inefficient. Nice of Mitsu to account for it as best possible.